Roofing Panel Hemming Tool

ABSTRACT

A hemming tool is used to hem a roofing panel having a base portion, a pair of standing ribs extending in a longitudinal direction along opposing sides of the base portion, and a tongue section extending from the base portion beyond the standing ribs, for use in a standing seam roofing system. The hemming tool comprises a panel support supporting to roof panel thereon such that the tongue section extends outward beyond a free edge of the panel support. A die member having a working surface, for engaging the tongue section of the roofing panel, is supported by a die support linkage such that the working surface of the die member is arranged for rolling engagement with the tongue section of the roofing panel about the free edge of the panel support from an upper surface to a lower surface of the panel support.

FIELD OF THE INVENTION

The present invention relates to a hemming tool for hemming a roofing panel comprising a base portion and standing ribs along opposing sides thereof in which the hemming tool is arranged to fold back a tongue section of the base portion which extends outward beyond ribs.

BACKGROUND

Many types of buildings make use of metal roofing panels in a standing seam roof panel system in which the roof panels generally comprise an elongate base portion with standing ribs along opposing longitudinally extending sides of the base portion. The standing ribs are joined to the standing ribs of adjacent panels for joining in an interlocking folded seam to cover the roof of the building. At the ends of the panels, typically at eaves of the roof, the roofing panels are typically finished by providing a tongue section on the base portion projecting beyond the standing ribs which is hemmed by a hemming tool to fold the tongue section back beneath the base portion of the roofing panel.

One example of a hemming tool is disclosed in U.S. Pat. No. 7,171,836 by Neudorf. The hemming tool in this instance operates similar to a press brake for folding sheet metal in which a planar member forces the tongue section to be folded against a panel support. The planar member is swung through an arc about the panel support through a range of approximately 140 degrees in a first stage of the folding. Completion of the hemmed end of the panel requires removal of the panel from the panel support to permit the continued folding of the tongue to be flattened at a 180 degree angle from the base portion of the panel. Disadvantages of the hemming tool include the requirement for a two stage operation to fully hem the end of the roof panel, as well as potential for the tongue section to not be tightly formed at the fold due to the distance of the planar folding member to the free edge of the panel support. The planar folding member tends to scuff or scratch the finish of the roof panel when positioned too close to the folded joint.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a hemming tool for hemming a roofing panel having a base portion and a pair of standing ribs extending in a longitudinal direction along opposing sides of the base portion arranged for connection with ribs of adjacent roofing panels of similar configuration in which the base portion includes a tongue section extending in the longitudinal direction beyond the ends of the ribs, the device comprising:

a main frame;

a panel support mounted on the main frame and comprising an end portion having an upper surface and a lower surface joined to the upper surface along a free edge of the panel support, the end portion being arranged to support the base portion of the roofing panel thereon such that the tongue section projects beyond the free edge and is arranged to be hemmed about the free edge;

a die member having a working surface arranged to engage the tongue section of the roofing panel supported on the panel support; and

a die support linkage supporting the die member on the main frame such that the working surface of the die member is arranged for rolling engagement with the tongue section of the roofing panel about the free edge of the panel support from a starting position of the die member at the upper surface of the panel support to an ending position of the die member at the lower surface of the panel support.

By providing a die member which is supported for rolling movement about a panel support member arranged to support a roof panel thereon, a tight folded edge can be formed on the end of the roof panel in a single operation without marking the finish of the roof panel as there is no relative sliding between the die member and the roof panel due to the rolling contact therebetween.

Preferably the working surface of the die member is curved about an axis lying substantially parallel to the free edge of the panel support.

Preferably the upper surface and the lower surface of the panel support are substantially parallel to one another such that the die member is arranged to fold the tongue section about the free edge from the upper surface to the lower surface through a range of approximately 180 degrees.

Preferably the free edge of the panel support is rounded between the upper surface and the lower surface.

In the preferred embodiment, the die support linkage comprises a link member supported on the main frame for pivotal movement relative to the panel support about a link axis lying parallel and adjacent to the free edge of the panel support in which the die member is supported on the link member for pivotal movement relative to the link member about a die axis lying parallel to the link axis.

Preferably the working surface of the die member follows a radius of curvature about the die axis.

The die member may comprise a segment of a roller having a radius which is near a distance between the link axis and the die axis.

Preferably the link axis is substantially centered between the upper and lower surfaces of the panel support and the die axis is rotatable with the link member about the link axis through a range of approximately 180 degrees.

A leading side of the die member may define a stop member against which the standing ribs of the roofing panel are arranged to be abutted when the tongue section projects beyond the free edge of the panel support in which the leading side of the die member is substantially perpendicular to the upper surface of the panel support in the starting position.

When a carriage member is supported on the main frame for upright sliding movement relative to the panel support, the die member and the die support link are preferably supported on the carriage member for sliding movement together therewith relative to the panel support between a loading position spaced above the panel support and a working position in which the die member is in close proximity to the panel support for engaging the roof panel.

There may be provided a clamp member is arranged to clamp the base portion of the roofing panel against the upper surface of the panel support directly adjacent the free edge of the panel support in which the clamp member spanning parallel to the free edge substantially a full width of the panel support. In this instance, the clamp member may be supported on the carriage member for sliding movement therewith relative to the panel support between the loading position and the working position.

According to a second aspect of the present invention there is provided a method of hemming a roofing panel having a base portion and a pair of standing ribs extending in a longitudinal direction along opposing sides of the base portion arranged for interlocking connection with ribs of adjacent roofing panels of similar configuration in which the base portion includes a tongue section extending in the longitudinal direction beyond the ends of the ribs, the method comprising:

providing a hemming tool a panel support having an end portion with an upper surface and a lower surface joined to the upper surface along a free edge of the panel support and a die member having a working surface;

supporting the base portion of the roofing panel on the end portion such that the tongue section of the roofing panel projects beyond the free edge of the panel support;

engaging the tongue section of the roofing panel against the upper surface of the panel support with the working surface of the die member;

rolling the working surface of the die member along the tongue section about the free edge of the panel support from a starting position at the upper surface of the panel support to an ending position at the lower surface of the panel support such that the tongue section is hemmed about the free edge of the panel support.

The method preferably includes providing a die support linkage comprising a link member supported on the panel support for pivotal movement relative to the panel support about a link axis lying parallel and adjacent to the free edge of the panel support and supporting the die member on the link member for pivotal movement relative to the link member about a die axis lying parallel to and spaced apart from the link axis.

The working surface of the die member is preferably formed to be curved along a radius of curvature about the die axis.

The method may further include positioning the upper surface and the lower surface of the panel support to be substantially parallel to one another and rotating the die member together with the link member about the link axis through a range of approximately 180 degrees from the starting position to the ending position.

The free edge of the panel support is preferably formed to be rounded about the link axis between the upper and lower surfaces of the panel support.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings like characters of reference indicate corresponding parts in the different figures.

FIG. 1 is a perspective view of the hemming tool.

FIG. 2 is a perspective of an opposing side of the hemming tool in which a portion of the frame is shown removed.

FIG. 3 is an end elevational view of the tool according to FIG. 2 in a loading portion of the tool.

FIG. 4 is an end elevational view of the tool in the working position with the die shown in a starting position.

FIG. 5 is an end elevational view of the tool in the working position with the die shown in an ending position.

FIG. 6 is an enlarged end elevational view of the die member in the starting position.

FIG. 7 is an enlarged end elevational view of the die in the ending position.

FIG. 8 is a perspective view of a roofing panel prior to the end being hemmed.

FIG. 9 is a side elevational view of the hemmed roof panel.

FIG. 10 is an enlarged perspective view of the hemmed end of the roof panel of FIG. 9.

FIG. 11 is a perspective view of an angled roof panel having a tongue section projecting from the end of the panel prior to hemming in which the end of the panel is oriented at an incline to the longitudinal direction of the panel.

FIG. 12 is a perspective view of the angled roof panel of FIG. 11 after hemming such that a hemmed edge of the roof panel is oriented at an incline to the longitudinal direction of the panel.

One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:

DETAILED DESCRIPTION

Referring to the accompanying figures there is illustrated a roof panel hemming tool generally indicated by reference numeral 10. The tool is particularly suited for hemming a roof panel 12 of the type used in a standing seam roof panel system.

The roof panel 12 typically comprises a base portion 14 which is elongate in a longitudinal direction and is integrally formed with a pair of standing ribs 16 extending upward along opposing longitudinally extending sides of the base portion 14. Each of the standing ribs 16 includes a hook formed at the upper free end thereof for interlocking connection with the standing ribs of adjacent roof panels in a folded standing seam when adjacent roof panels of similar configuration are mounted adjacent one another. The roof panel further comprises a tongue section 18 of the base portion projecting from the end of the roof panel in the longitudinal direction beyond the ends of the ribs 16. Prior to hemming, the tongue section is parallel and coplanar with the base portion 14 to extend outward in the longitudinal direction therefrom as shown in FIG. 8. After hemming, the tongue section 18 is folded through a range of approximately 180° downwardly and rearwardly under the base portion to define a hemmed edge 20 a shown in FIGS. 9 and 10 which is spaced slightly outward in the longitudinal direction from the plane of the ends of the standing ribs.

The tool 10 comprises a main frame having two side members 22 in the form of elongate and upright plates mounted parallel to one another and spaced apart from one another in a lateral direction. Two cross members 24 are mounted to extend horizontally between the two side members 22 at vertically spaced positions adjacent the bottom ends of the side members to support the two side members in fixed relation with one another.

A panel support 26 is also mounted to extend between the two side members spaced above the cross members 24 at an intermediate location along the two side members to define a horizontal shelf upon which a roof panel can be supported while being hemmed. The panel support is formed from a generally flat plate 28 mounted horizontally and spanning in the lateral direction substantially the full width at a main portion 30 spanning rearwardly from the two side members to be supported in relation to the side members by respective support arms 32. The support arms 32 extend rearward beyond the rear side of the two side members to support the main portion of the panel support extending rearward thereon to a rear edge 34 of the panel support which is sloped downwardly and rearwardly for ease of loading a roof panel onto the upper surface 36 of the panel support.

The plate 28 forming the panel support further comprises an end portion 38 projecting forwardly from the main portion between the two side members in which the end portion 38 is narrower in the lateral direction than the space between the two side members to define a gap in the lateral direction between each of the laterally opposed ends of the end portion 38 and the respective side member of the main frame adjacent thereto. The upper surface 36 of the end portion 38 is also flat and horizontal to be continuous with the main portion. The opposing lower surface 40 of the end portion of the panel support is parallel to the upper surface and spaced therebelow only by the thickness of the plate 28 defining the panel support. The upper surface 36 and the lower surface 40 are joined with one another at a front end which is rounded or semi-circular in profile and which defines a free edge 42 about which the tongue section 18 of the roof panel is arranged to be hemmed.

Just prior to hemming the roof panel, the roof panel is clamped against the upper surface 36 of the panel support by a suitable clamp member 44. The clamp member spans substantially the full width in the lateral direction between the two side members of the main frame while being slightly shorter than the space between the two side members so as to permit the clamp member to be received between the standing ribs of the roof panel. The clamp member comprises a flat clamp edge 46 along the bottom side thereof arranged to engage the top side of the base portion of the roof panel between the two standing ribs. The front or leading side 48 of the clamp member is oriented to be substantially perpendicular to the upper surface of the panel support and is arranged to be aligned in close proximity to the free edge 42 of the panel support near the ends of the standing ribs so as to be directly adjacent the free edge substantially along the full width thereof.

The clamp member 44 is supported on a carriage member 50 which is supported on the two side members 22 of the main frame above the panel support for vertical sliding movement relative to the main frame and panel support. The carriage member 50 comprises a main body 52 in the form of a crossbar spanning between opposed ends which are elongate in an upright direction for being matingly and slidably received within respective vertically oriented carriage slots 54 in the two side members 22 respectively. The clamp member 44 is fixed onto the main body 52 of the carriage member for vertical sliding movement therewith between a loading portion spaced above the panel support to receive a roof panel therebetween and a working position in which the clamp member is slidably displaced vertically downward towards the panel support in relation to the loading position for clamping the roof panel against the upper surface of the panel support.

Vertical sliding movement of the carriage member 50 is controlled by a carriage arm 56 pivotally supported on the one of the side members 22 at an exterior side thereof. A pivot shaft 58 extends in the lateral direction between opposing ends rotatably supported on the two side members 22 respectively so as to be parallel to the free edge and spaced vertically thereabove adjacent the top end of the two side members. The carriage arm 56 is fixed to one of the ends of the pivot shaft 58 for pivotal movement therewith about a longitudinal axis of the pivot shaft which is parallel to the free edge.

A pair of crank arms 60 are fixed at opposing ends of the pivot shaft adjacent the interior sides of the two side members 22 so that the two crank arms 60 both extend radially outward from the pivot shaft in a common radial direction. The direction of the crank arms is initially directed substantially vertically upward in the loading position and prior to being pivoted downwardly and rearwardly through approximately 180° towards the working position where the crank arms extend substantially vertically downward.

At each end of the carriage member 50 there is provided an intermediate link 62 which is pivotally coupled at one end to the top end of the carriage member and which is pivotally coupled at an opposing end to the free end of the respective crank arm 60. The intermediate links are each curved to be substantially C-shaped about the pivot shaft from the crank arms 60 extending thereabove to the carriage body therebelow in the loading position. An upright projection formed on each intermediate link 62 functions as a stop 64 which engages the pivot shaft and prevents further rotation of the crank arms about the pivot shaft beyond the working position when rotated away from the loading position.

The carriage arm 56 is fixed to the end of the pivot shaft to be oriented to project substantially forwardly in a generally horizontal orientation in the loading position such that upward and rearward rotation of the crank arm 56 over-center through a range of approximately 180° causes rotation of the pivot shaft together therewith to displace the carriage member 50 vertically from the loading position to the working position.

Once the roof panel is clamped in the working position of the clamp member, a die member 66 of the tool is used to hem the edge of the roof panel about the free edge of the panel support. The die member 66 is carried by a die support linkage 68 for movement relative to the main frame such that a working surface 70 of the die member is arranged for rolling engagement with the tongue section of the roofing panel about the free edge of the panel support from a starting position of the die member at the upper surface of the panel support to an ending position of the die member at the lower surface of the panel support.

The die support linkage 68 comprises a main link body 71 extending laterally substantially a full width between the two side members for being pivotally supported at laterally opposed ends on the main body 52 of the carriage member by respective end plates 72 fixed onto the ends of the carriage body. The two end plates 72 are oriented perpendicular to the lateral direction and project forwardly from opposing ends of the carriage body for pivotally supporting the link body 71 spanning therebetween for pivotal movement relative to the carriage body and the main frame upon which it is supported about a link axis which spans horizontally in the laterally direction parallel to the free edge of the panel support. The link axis is positioned adjacent the free edge of the panel support in the working position of the carriage so as to be centered between the upper and lower surfaces of the panel support with the free edge being curved about the link axis with a continuous radius from the upper surface to the lower surface.

The die member spans the full width of the free edge in the laterally direction and is supported at opposing ends on the opposing ends of the link member in the lateral direction such that the die member is pivotal relative to the link member about a die axis 76 which is parallel and spaced radially outward from the link axis 74. The die member 76 is pivotal about the die axis relative to the link member in the working position of the carriage from the starting position in which the die axis is in a vertical plane with the link axis spaced vertically thereabove so that the die member extends downward from the axis to the working surface 70 at the bottom end thereof to an ending position in which the die axis has been rotated forwardly through an arc of approximately 180° to be positioned in a vertical plane with the link axis spaced below the link axis.

In the starting position the working surface of the die member is in proximity to the bottom clamp edge 46 of the clamp member so that the die member and the clamp member together clamp the roof panel against the upper surface of the panel support. The working surface is arranged for rolling engagement with the tongue section of the roof panel by forming the working surface to be curved to follow a radius of curvature about the die axis spaced outwardly from the free edge of the panel support.

The radius between the die axis and the working surface corresponds approximately to the distance between the link axis at the free edge and the die axis spaced outwardly from the free edge. More particularly the radius between the die axis and the working surface corresponds to the vertical distance between the die axis in the starting position and the upper surface of the panel support minus the thickness of material of the base portion of the roofing panel received between the die member and upper surface of the panel support.

The working surface remains freely pivotal about the die axis with the die member through pivotal movement of the die member from the starting position to the ending position. The curvature of the working surface effectively corresponds to a segment of a roller of constant diameter which is concentrically rotatable about the die axis on the die member. As the die member is freely floating and freely pivotal about the die axis from the starting position to the ending position, there is no relative sliding between the working surface and the roof panel, but only rolling contact of the working surface engaged with the roof panel from the starting position at the upper surface to the ending position at the lower surface.

A control arm 78 is coupled to the link body by a shaft extending in the lateral direction through one of the side members to the exterior side thereof. A suitable control arm slot 80 is positioned vertically in the side member for receiving the pivot shaft of the control arm 78 slidably therein as the die member is displaced with the carriage member upon which it is supported between the loading and working positions thereof. The die member pivots from the starting position to the ending position thereof only in the working position of the carriage assembly. The control arm 78 extends radially outward from the die axis to initially be positioned to extend upward at a slight rearward incline in the starting position. The control arm 78 is rotated forwardly over centre to a downward orientation which is near vertical in the ending position. The control arm 78 is thus displaced through a downward motion for ease of forming the hemmed edge from the starting position to the ending position of the die member.

In the starting position, a rear face 82 of the die member is oriented substantially vertically and perpendicularly to the upper surface of the panel support to define a stop member against which the standing ribs of the roof panel are arranged to be abutted prior to hemming the tongue section of the roof panel.

In use, the user initially positions the die member in the starting position on the carriage assembly positioned in the loading position spaced above the panel support. Once a roof panel is placed on the panel support with the ends of the standing ribs in close proximity to the free edge such that the tongue section projects beyond the free edge of the panel support, the user first rotates the carriage arm 56 upwardly and rearwardly over center to the working position to displace the clamp member and die member downwardly into engagement with the roof panel clamped against the upper surface of the panel support.

Subsequent over center rotation of the control arm 78 of the die member forwardly and downwardly over center causes the die axis to be rotated downwardly and forwardly through approximately 180° from the starting position to the ending position. Engagement of the working surface of the die member with the tongue section of the roof panel causes a rolling engagement of the die member with the roof panel which follows the profile of the rounded free edge of the panel support from the upper surface to the lower surface thereof to cause the tongue section to be bent through a range of 180° about the free edge of the panel support.

The resulting hemmed edge as shown in FIGS. 9 and 10 comprises a tongue section which projects forward by a few millimetres beyond the ends of the standing ribs and then follows a rounded profile of the free edge of the panel support so that the remaining portion end portion of the tongue section is parallel to and below the base portion of the roof panel. Returning the die member to the starting position and the carriage member to the loading position permits the roof panel to be slidably removed forwardly from the tool 10.

The tool 10 can also be configured for similar operation in hemming the end of an angled roof panel where the end of the roof panel lies at an inclination to the longitudinal direction of the roof panel such that one of the standing ribs is shorter than the other in the longitudinal direction as shown in FIGS. 11 and 12. In this instance, the hemmed edge of the roof panel is formed in a similar manner by positioning of the roof panel onto the panel support of the tool such that the edge to be hemmed is parallel along the free edge of the panel support. The die is supported on the die support linkage in a similar manner for rolling movement about a die axis which is movable through a range of 180 degrees about a link axis parallel thereto and extending along the free edge of the panel support as described above. The tool in this instance differs only in the repositioning of some components of the tool to accommodate a roof panel positioned horizontally, but with the longitudinal direction thereof oriented at an inclination to the free edge of the panel support instead of being perpendicular as in the illustrated embodiment.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense. 

1. A hemming tool for hemming a roofing panel having a base portion and a pair of standing ribs extending in a longitudinal direction along opposing sides of the base portion arranged for connection with ribs of adjacent roofing panels of similar configuration in which the base portion includes a tongue section extending in the longitudinal direction beyond the ends of the ribs, the device comprising: a main frame; a panel support mounted on the main frame and comprising an end portion having an upper surface and a lower surface joined to the upper surface along a free edge of the panel support, the end portion being arranged to support the base portion of the roofing panel thereon such that the tongue section projects beyond the free edge and is arranged to be hemmed about the free edge; a die member having a working surface arranged to engage the tongue section of the roofing panel supported on the panel support; and a die support linkage supporting the die member on the main frame such that the working surface of the die member is arranged for rolling engagement with the tongue section of the roofing panel about the free edge of the panel support from a starting position of the die member at the upper surface of the panel support to an ending position of the die member at the lower surface of the panel support.
 2. The tool according to claim 1 wherein the working surface of the die member is curved about an axis lying substantially parallel to the free edge of the panel support.
 3. The tool according to claim 1 wherein the upper surface and the lower surface of the panel support are substantially parallel to one another such that the die member is arranged to fold the tongue section about the free edge from the upper surface to the lower surface through a range of approximately 180 degrees.
 4. The tool according to claim 1 wherein the free edge of the panel support is rounded between the upper surface and the lower surface.
 5. The tool according to claim 1 wherein the die support linkage comprises a link member supported on the main frame for pivotal movement relative to the panel support about a link axis lying parallel and adjacent to the free edge of the panel support, the die member being supported on the link member for pivotal movement relative to the link member about a die axis lying parallel to the link axis.
 6. The tool according to claim 5 wherein the working surface of the die member follows a radius of curvature about the die axis.
 7. The tool according to claim 5 wherein the die member comprises a segment of a roller having a radius which is near a distance between the link axis and the die axis.
 8. The tool according to claim 5 wherein the link axis is substantially centered between the upper and lower surfaces of the panel support.
 9. The tool according to claim 5 wherein the die axis is rotatable with the link member about the link axis through a range of approximately 180 degrees.
 10. The tool according to claim 1 wherein a leading side of the die member defines a stop member mounted on the frame against which the standing ribs of the roofing panel are arranged to be abutted when the tongue section projects beyond the free edge of the panel support in the starting position.
 11. The tool according to claim 10 wherein the leading side of the die member is perpendicular to the upper surface of the panel support in the starting position.
 12. The tool according to claim 1 wherein there is provided a clamp member arranged to clamp the base portion of the roofing panel against the upper surface of the panel support, the clamp member spanning parallel to the free edge substantially a full width of the panel support.
 13. The tool according to claim 1 wherein there is provided a clamp member arranged to clamp the base portion of the roofing panel against the upper surface of the panel support directly adjacent the free edge of the panel support.
 14. The tool according to claim 1 wherein there is provided a carriage member supported on the main frame for upright sliding movement relative to the panel support, the die member and the die support link being supported on the carriage member for sliding movement together therewith relative to the panel support between a loading position spaced above the panel support and a working position in which the die member is in close proximity to the panel support for engaging the roof panel.
 15. The tool according to claim 14 wherein there is provided a clamp member arranged to clamp the base portion of the roofing panel against the upper surface of the panel support, the clamp member being supported on the carriage member for sliding movement therewith relative to the panel support between the loading position and the working position.
 16. A method of hemming a roofing panel having a base portion and a pair of standing ribs extending in a longitudinal direction along opposing sides of the base portion arranged for interlocking connection with ribs of adjacent roofing panels of similar configuration in which the base portion includes a tongue section extending in the longitudinal direction beyond the ends of the ribs, the method comprising: providing a hemming tool a panel support having an end portion with an upper surface and a lower surface joined to the upper surface along a free edge of the panel support and a die member having a working surface; supporting the base portion of the roofing panel on the end portion such that the tongue section of the roofing panel projects beyond the free edge of the panel support; engaging the tongue section of the roofing panel against the upper surface of the panel support with the working surface of the die member; rolling the working surface of the die member along the tongue section about the free edge of the panel support from a starting position at the upper surface of the panel support to an ending position at the lower surface of the panel support such that the tongue section is hemmed about the free edge of the panel support.
 17. The method according to claim 16 including providing a die support linkage comprising a link member supported on the panel support for pivotal movement relative to the panel support about a link axis lying parallel and adjacent to the free edge of the panel support and supporting the die member on the link member for pivotal movement relative to the link member about a die axis lying parallel to and spaced apart from the link axis.
 18. The method according to claim 17 including forming the working surface of the die member to be curved along a radius of curvature about the die axis.
 19. The method according to claim 17 including positioning the upper surface and the lower surface of the panel support to be substantially parallel to one another and rotating the die member together with the link member about the link axis through a range of approximately 180 degrees from the starting position to the ending position.
 20. The method according to claim 17 including forming the free edge of the panel support to be rounded about the link axis between the upper surface and the lower surface of the panel support. 